To meet the demand for wireless data traffic, which has increased since deployment of 4th-generation (4G) communication systems, efforts have been made to develop an improved 5th-generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post long-term evolution (LTE) system’.
It is considered that the 5G communication system will be implemented in millimeter wave (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To reduce propagation loss of radio waves and increase a transmission distance, a beam forming technique, a massive multiple-input multiple-output (MIMO) technique, a full dimensional MIMO (FD-MIMO) technique, an array antenna technique, an analog beam forming technique, and a large scale antenna technique are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a device-to-device (D2D) communication, a wireless backhaul, a moving network, a cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, a hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and a sliding window superposition coding (SWSC) as an advanced coding modulation (ACM) scheme, and a filter bank multi carrier (FBMC) scheme, a non-orthogonal multiple Access (NOMA) scheme, and a sparse code multiple access (SCMA) scheme as an advanced access technology have been developed.
In a downlink (DL)/uplink (UL) in a wireless communication system supporting an orthogonal frequency division multiple access (OFDMA) scheme, inter-cell interference (ICI) may significantly degrade performance of a signal receiving apparatus. If a reference signal (RS), e.g., a pilot signal used for estimating a channel or measuring the channel in the signal receiving apparatus is distorted due to effect of the ICI, performance of the signal receiving apparatus may be significantly degraded.
For example, most of communication systems supporting an OFDMA scheme such as an LTE use various schemes, e.g., a scheme of differently setting a location of an RS used in each of cells, a scheme of power boosting an RS compared to a data signal, e.g., a data symbol, and/or the like for minimizing distortion of the RS in a situation in which there is ICI.
For example, a DL in an LTE mobile communication system defines that neighbor base stations (BSs) shift cell-specific reference signals (CRSs) on a frequency axis on a specific CRS based on different offsets to transmit the shifted CRSs, and a BS power boosts a CRS with transmission power greater than transmission power applied to a data signal to transmit the power boosted CRS. The term BS may be interchangeable with the term node B, evolved node B (eNB), evolved universal terrestrial radio access network (E-UTRAN) node B (eNB), access point (AP), and the like.
The schemes as described above decrease a degree in which an RS is distorted due to ICI, so the schemes may prevent relatively significant degradation of channel estimation performance and channel measurement performance of a signal receiving apparatus.
However, the power boosted RS as described above operates as ICI to a data signal included in a target signal, so the power boosted RS results in a non-Gaussian characteristic of an interference signal.
Meanwhile, most of current communication standards supporting an OFDMA scheme differently set locations of RSs used in neighbor cells, so effect of boosted interference RS is not reflected in a received RS.
So, in a general LTE mobile communication system, a channel decoding operation using a log-likelihood ratio (LLR) calculated on an interference environment which has a non-Gaussian characteristic may not reflect effect of a boosted interference RS, so the channel decoding operation may significantly degrade channel decoding performance of a signal receiving apparatus.
In a general LTE mobile communication system, a scheme of retransmitting a signal based on an HARQ scheme has been implemented. In the general LTE mobile communication system, a retransmitting operation may be performed based on one of HARQ retransmission schemes, e.g., a chase combining (CC) scheme, an incremental redundancy (IR) scheme, a partial IR scheme, and/or the like. All of the CC scheme, the IR scheme, and the partial IR scheme are suitable for a case that it is difficult to detect a damaged part of a codeword transmitted by a signal transmitting apparatus, and a damage due to a channel and a damage due to an interference signal regularly occur within one codeword.
As described above, in the DL/UL network which is based on the OFDMA scheme, a case that a statistical characteristic of an interference signal does not regularly damage a codeword frequently occurs. For example, whether an interference signal is conflicted may be varied on a resource block (RB) basis, so a degree in which a signal is damaged may be varied on an RB basis within a codeword. Further, there is a reference signal (RS) which needs to be transmitted within an RB, so an interference characteristic and a degree in which a signal is damaged due to this may be varied per resource element (RE) group.
However, retransmission schemes proposed up to now do not consider an interference characteristic.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.